1. Technical Field
This invention relates to the technology of friction welding or friction soldering, and more particularly to bonding conductive metallic members to fragile non-metallic parts, such as glass.
2. Discussion of the Prior Art
The earliest use of friction welding was to merge together two stiff conductive metal parts, such as two rods, one being rapidly rotated while it was pressed with a linear forging force against the end of the other rod end that remained relatively stationary; this caused interactive friction to melt the mating end surfaces. Recrystallization to a solid metallic joint occurred upon removal of the rotary-forging force. Sometimes a meltable solder was placed adjacent to the friction generating surfaces to be the melted as a substitute for melting the surface of the parts; such meltable solder, when recrystallized, created the bond between the parts.
Friction welding was adapted to the electrical industry. A conductive lead pin was rotated and forged to a conductive plug or head (see U.S. Pat. No. 4,542,843). Particular care had to be taken to allow the plug to rotate with the pin when the metallic interface between the pin and plug began to melt. In some cases the rotary motion was replaced by a vibrating motion, provided one member or part was soft and ductile enough to be deformed by pressing of the tool therebetween and thus ensure a frictional interengagement at a desirable location (see U.S. Pat. No. 5,288,006).
A special problem in the automotive industry which has never been addressed by the technology of friction welding is the need for joining terminals of electrical wires or leads that are embedded in glass windows, such as a vehicle windshield, backlite (the rear window) or body glass. Such wires can serve as a radio or cellular phone antenna, heater, security circuit, or keyless entry means. Such terminals may be a conductive clip arranged at a location on the perimeter of the glass which receives the end of a wiring harness that will extend into the vehicle interior to be operative. The clips are currently bonded to the glass by adhesives, or are soldered using hot air, flame, resistance heating, or other external heating methods that risk cracking the glass.